The ability of ultraviolet light to kill of destroy micro-organisms in air or liquid is well known. Ultraviolet light has successfully been employed as a purifying or sterilizing technique in both domestic and small-scale industrial applications. Its germicidal qualities, however, in any given application, depends in part upon the intensity of the ultraviolet light, the fluid exposure time to the light and the light transmission quality of the fluid itself. There has been a recent trend towards "thin film" ultraviolet radiation whereby a thin film or layer of the fluid to be purified is constrained to pass in close proximity to an elongate ultraviolet ray emitting source which itself is normally covered or surrounded by a protective quartz jacket or sleeve. The thin film passage of the fluid may be in a direction which parallels the elongate axis of the ultraviolet lamp as disclosed, for example, in Canadian Pat. No. 1,062,437-Lewis, issued Sept. 18, 1979 or perpendicular thereto as disclosed, for example, in U.S. Pat. No. 3,837,800-Wood, issued Sept. 24, 1974. Both of these thin film ultraviolet purifying or sterilizing designs are intended for use in a closed fluid supply system wherein the fluid which is in close proximity to the lamp units does not contact the lamp ends and their attendant electrical interconnection with a source of electric power. In other words, the free ends of the ultraviolet lamps witin its associated sleeve or jacket of a closed system are not designed to be themselves immersed in water although removal and replacement of burned out lamps can be a relatively simple task. In addition to their inability to be water immersed, these known thin-film closed ultraviolet purification systems are relatively costly to manufacture and individually limited in handling many industrial fluid throughout requirements found in existing water purification plants and waste water treatment facilities. Moreover, whether or not ultraviolet irradiation is achieved using the thin-film principle, closed systems are not readily adaptable and installed in existing water or effluent facilities where the fluid to be treated flows through open containment streams, channels, sluices or the like.